Yeast Appears to Benefit Foals' Intestinal Flora

If your broodmare has a “bun in the oven,” that bun might benefit from some live yeast, French researchers say. No, the yeast isn’t meant to make the bun rise, but it could give your foal's digestive system a better start in life.

“Our results, albeit preliminary, lead us to believe that Saccharomyces cerevisiae boulardii yeast could favor the early establishment of a stable and diversified intestinal flora in the foal, starting at birth,” said Jean-Marc Betsch, DVM, clinician and researcher at the Méheudin Equine Clinic and veterinary training facility in Ecouché, and ad-hoc professor at the National Veterinary School of Maisons-Alfort. He presented his research at the 2014 French Equine Research Day held March 18 in Paris.

Betsch and colleagues studied 20 Welsh pony foals for two purposes: First, to determine when and how intestinal flora begins to establish, and, secondly, to know if adding yeast—a probiotic—to the mare or foal’s diet could improve the intestinal flora.

Via fecal analysis provides, Betsch said his group determined that intestinal microflora establishes within the first day of life with rapid bacterial colonization.

Then Betsch’s team evaluated the effects of yeast in the foals' diet. They separated the foals into four groups:

Mares received daily yeast supplements eight days before term until four days after foaling;

Foals received daily yeast supplements for the first seven days of life;

Foals received a double dose of daily yeast supplements for the first seven days of life; and

Mares and foals received daily placebos (dextrose) to serve as study controls.

The researchers found that foals in the three treatment groups tended to have less diarrhea and a more stable and more diversified intestinal flora population based on fecal analyses, compared to the control group, Betsch said. The treated foals had more “good” and less “bad” bacteria in their feces—probably because much of the bad bacteria, such as Escherichia coli and Clostridium difficile, are aerobic, meaning they need oxygen to survive. The Sc boulardii yeast consumes oxygen in the intestines, making the environment less favorable for these harmful bacteria, he said.

Foals in the double-dose treatment category had even less harmful bacteria, said Betsch. However, these foals' feces tended to be foul-smelling and lighter in color.

Additionally, the foals' average daily weight gain in the first 20 days of life was significantly greater in the mare-treated group compared to the control group, Betsch said. The foal-treated, single-dose group had better weight gain than controls as well, but not as much as the mare-treated group. The single-dose group gained slightly more weight than the double-dose group.

“When given to the mare 10 days prior to foaling, Sc boulardii live yeast can have a beneficial effect on the intestinal health and food digestibility of the foal, favoring growth and contributing to an effective prevention of early diarrhea,” Betsch said.

Disclaimer: Seek the advice of a qualified veterinarian before proceeding with any diagnosis, treatment, or therapy.